Intraoperative angiography was performed in 136 cases of surgical reconstruction of the aorta, iliac, femoral and carotid arteries. In 39 cases pathological angiograms were found at operation, some of them quite unsupected. The most common pathological finding was non-occluding thrombosis, but intimal lesions caused by vessel clamps and incomplete endarterectomies were not uncommon. Immediate surgical reexploration and revision resulted in a high frequency of open reconstructions at follow-up, which was performed 1--24 months postoperatively. On the other hand, nonrevised reconstructions with pathological angiograms usually failed in the early postoperative period. In cases with normal intraoperative angiograms the result at follow-up was excellent. In addition to electromagnetic flow determination, intraoperative angiography is a most valuable adjunct in the assessment of vascular surgery during operation and should be used more frequently. All pathological findings in the angiograms must be seriously considered and lead to reexploration and revision.